Thermostatic control switches for refrigerators and the like



June 2, 1964 c. w. KUHN ETAL 3,135,849

THERMOSTATIO CONTROL SWITCHES FOR REFRIGERATOR'S AND THE LIKE- Filed Feb. 28, 1962 9 Sheets-Sheet l 36- 30g 30h Q0 i 34 a' Ag A umm El2,/49

sof W i l und@ 40 June 2, 1964 c. w. KUHN ETAI. 3,135,849

THERMOSTATIC CONTROL SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 28, 1962 9 Sheets-Sheet 2 June 2, 1964 c. w. KUHN ETAL. 3,135,849

THERMOSTATIC CONTROL SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 28, 1962 v 9 Sheets-Sheet I5- eo 54A 54a 62e 54a 541 309 44 54e 54e 30g 6 Y sob sob- June 2, 1964 c. w. KUHN ETAL 3,135,849

THERMOSTATIC CONTROL SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 28, 1962 9 Sheets-Sheet 4 54a 54h 54C Jne 2, 1964 c. w. KUHN r-:TAL

THERMOSTATIC CONTROL- SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 28. 1962 THERMOSTATIC CONTROL SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 28, 1962 June 2, 1964 c. w. KUHN ETAL 9 Sheets-Sheet 6 sled ' llllll llli- June 2, 1964 c. w. KUHN l-:TAL 3,135,849

THERMOSTATIC CONTROL SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 28, 1962 9 Sheets-Sheet '7 June 2, 1964 c. w. KUHN ETAL 3,135,849

THERMOSTATIC CONTROL SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 28, 1962 9 Sheets-Sheet 8 cg, x8 30g 6030A /mzl 7"" Z /04 36`i los l Il I I :wu 4a n 60C I, l

June 2, 1964 c. w. KUHN 'E1-Al. 3,135,849

THERMOSTATIC CONTROL SWITCHES FOR REFRIGERATORS AND THE LIKE Filed Feb. 2s, 1962 9 sheets-sheet 9 46 wzo "lf IHA 3,135,849 THERMOSTATIC CNTROL SWITCHES FOR REFRIGERATGRS AND THE LIKE Clarence W. Kuhn, Wauwato'sa, and Charles -Roy Smith,

Meqilon, Wis., assignors to Cutler-Hammer, Inc., Mil- .waukee Wis., a corporation of Delaware Filed Feb. 28, 1962, Ser. No. 176,354

24 Claims. .(Cl. Mtl- 140) being setup intherswitch and operating mechanism.`

Such stresses affect the repetitive accuracy of operation,

and over periods of time cause deteriorationvor falloit United States Patent YC) Y" 3,135,849 Patented June 2, 1964 ICC The accompanying drawings illustrate preferred embodiments whichwill now bedescribed in detail, it being understood that the embodiments illustrated are susceptible of various modifications without departing from the scope of the appended claims.

In the drawings:

'FIGURE 1 is a side elevation view of a thermostatic control-switch constructed in accordance with the invention;

FIG. Z is a right end View of the controlswitch shown in FIG. 1;

FIG. 3 is a View in cross section taken along the line 3-3 of'FlG. 2;

FIG. 4 is a view like FIG. 3 but showing the control vswitch in another operating condition; v

'FIG. 5 is a top plan view with a cover removed to show interior mechanism;

FIG. 6 is a View in cross section taken along the line .6-6 of FIG. 3;

in calibration settings. VThermostatic control switches Y' lutilizing diaphragm type thermal power elements that eliminate the need for range or calibration loading springs lhave heretofore been proposed,l but their designs have left something to be desired in respect of operation accuracy and quality control in repetitive high` quantity manufacture. It is therefore a lprimary object of the present invention to provideV improved forms of thermostatic switches employing diaphragm power` elements and other construction which eliminate 'the use ofconventional diaphragm loading springs.

` Another object is toprovide a kbasic form of thermostatic control switch of the aforementioned kind which by substitution and/ or addition ofl but a` few parts can provide several different versions in respect 'of range adjustment of cut-in and cut-out points, `and with or without auxiliary alarm contacts.

A further object` is to provide in a control switch of the aforementionedV character an improved snap acting switch Vmechanism which has two stable operating conditions and provides fast make and break contact'operation when positively driven fromone tol another V'of its stable operating conditions. f

A kstill further object is to provide in a control switch of the aforementioned kind a novel and improved form ,lof motion' transmitting and amplifying mechanism which affords drive of said snap actingswitch mechanism from one to the other of its stable'operating conditions and `vice versa, 1in response to inward and outward movementsl of the power element diaphragm 'without'v subjecting the latterto any appreciable loading.

A more specific object is to provide a motion transmitting and amplifying:mechanismwhichis characterized by having separate levers for driving the operating meme ber ofthe snap acting switch mechanism in opposite Vdimechanism unaffected byrange or differential adjustments.` j Y v An additional specific object is toprovidc in amotion transmitting'and amplifying mechanism; for yindividual 'rections withy lost 'motion thereby. rendering theV switch adjustments of the points vat whichr the` aforementioned I? separate levers arefeachweffective to drivetheoperating membertonposition 'affording operationof said switch mechanism fromone to theother of said stable Yoperating conditions vice versa, andYK f l A furtherwspeciioobject is tof yprovide an adjusting me'ch'anisnfor the aforementionedlever;system whichV requires low, constant: operating'torque to' effect changes 'in range settings in either direction.

n ""fQther vobjectsand advantages of the `invention will Y hereinafter appear(` Y 'fstantially constant.

FIG. l2 is a fragmentary view taken along the liney ki12-12 of FIG. 3;

FiG. 13 is a top plan view of a part in rthe switch mechanism; FIG. A14 is a view'like FIGS. 3 and 4 but showing a modified version of the thermostatic control switch;-

FIG. l5` is a View in cross section taken along the line l5- 1S of FIG. 14;

FIG. 16 is a view showing inexploded relation the yparts of the modified lever assembly used in the version shown in FIGS. 14 and 15; i FIG. 17y is a view like FIG. 5, but showing a second `modified versiony of thermostatic control switch;

FIG. 18 is a Vfragmentary cross sectional view taken along the line 18-18 of FIG. 17; j FIG. 19 is a view showing certain parts of the modified Version of FIGS. 17 and 18 in exploded relation;V

FIG. 20 is a view like FIG. 18 but showing 'a third modified version of a thermostatic control switch; l

FIG. 2l isl a View showing certain'portions of -the modified version of FIG.` 2() in exploded relation;

' IFIG; 22 shows one operating condition of lcertain partsY used in the switch mechanisms of all versions of the conf FIG. '-23 is alike F1o; 22 but shows the sameparts in "case 32, anda range adjusting 'knob 34. This form is a :so-called straight range version wherein cut-in 'and cut-out` points arev simultaneously adjustable vwhile rmaintaining lthe differential between such: points sub'- `Power element 3i? is provided witlra cupshaped porftiona, a pair of side'fr'arne portions 30bwhich integrally join withportion 30a on opposite sidesy at the upper end ofthe latter. At corresponding end portions f Sllb are provided with integral tabs 30e (seeFIG. 5) which extend through slots in a mountingV bracket 36-and are upset over the opposite side of bracket 36 to secure the latter in place.

As best shown in FIGS. 3 and 4, power element 30 is -provided with a diaphragm 30d which is suitably secured in a sealed relation to the inner wall of the cup portion 30a to form an enclosed diaphragm chamber 38 therewith. A capillary tube 40 penetrates and is sealed to a boss portion 30e which extends downward at one side of the underside of portion 30a. Tube 40, as is well known, is of some definite length andl its bore and diaphragm chamber 38 of element 30 are provided with a suitable till of gas such as Freon (F-22 or F-l2) or methyl chloride. Diaphragm 30d is preferably formed in accordance with the teaching of the Smith Patent No. 2,751,935 so that it will move outwardly and in- Wardly in a linear relation to changes in pressure of the gas in the chamber 38 and tube 40.

A base 42 formed of a suitable molded electric insulating material seats at its lower end against the upper edge of cup-portion 30a on opposite sides between the side from portion 30a and at one end against bracket 36. Tabs 30]c struck out of the portions 30b are bent into recesses 42a (see FIGS. 1 and 5) formed in the outer surfaces of the aforementioned sides of base 42 and serve to` secure the latter and power element 30 in assembled relation.

A cover 44 formed `of a suitable insulating material seats against the upper surface of base 42 and is secured in place by inwardly extending tabs 30g formed along the upper edges of the portions 30b.

QA stationary contact 46 is mounted on an arm 48a of stationary contact terminal member 48 (see FIGS. 5 Iand 11) that seats within base 42 where it is secured by a screw 50. A movable contact 52 is secured in overlying working relation to contact 46 to thefree end of a central hollow rectangular portion 54a of a metallic reed member 54 which is of a form best shown in FIG. 13. At its other end member 54 is provided with spaced apart openings to accommodate screws 56 which also penetrate the arm 58a of a terminal member 58 that overlies and'contacts the last mentioned end of member 54 to securethe latter and terminal member 58-in place in base 42. v

As shown in FIG. 13, member 54 is provided with legs 54b which are spaced apart and extend parallel with the longitudinal sides of the portion 54a. At their outer ends the portions 54b have integral portions 54el that extend inwardly toward a tab 54d integrally formed on the free end of portion 54a. Portions 54e have hooked lips 54e that extend generally parallel with the portions 54b.

Reed member 54 kis formed to accurate dimensions by suitably blanking the same from thin flat stock of a spring vtemper material, such as beryllium copper alloy. VMounting recessesfor member 54 and terminal member 58 are so formed that when the same are initially secured tin base 42 by screws `56 contact 52 will be forced into to pivot clockwise, the vertical component of force ex- Y engagement with contact 46 with some pre-bending of the portion 54a thereby establishing a minimum normal notch 62a formed in one end of a molded drive lever -Y 62. Flipper springr 60 is formed by blanking from thin `flat stock of stainless steel which has been suitably heat .treated and tempered.

The CVV-shape conliguration of spring 60 is imparted in assembling it to the reed mem- .ber 54 and drive lever.62, but preformed y(-shape springs can also be used.

Drive lever 62 4at its opposite end is provided with a 4 V-shaped notch 62b that engages on the inner edge of the portion 54a of member 54 to provide a pivot fulcrum point for lever 62. As viewed in FIG. 3, notch 62a is below the plane of member 54 and the forces developed in spring 60 hold the tab 54d in engagement with a lateral stop finger 58d integrally formed with terminal member 58. vIn such position of' member 54 contact 52 is held out of engagement from contact 46 thereby interrupting circuit.

If drive lever 62 is pivoted counterclockwise about its pivot fulcrum at notch 62b the end 60e ofV spring 60 will move upwardly and be compressed, and the upward component of force exerted by spring 60 on the 'member 54 decreases as the angle between its ends and the plane of kmember 54 decreases. A null point is reached where the upward force exerted by spring 60 is equal to the downward force exerted by member 54 due to its aforementioned bending. Any further counterclockwise movement of lever 62 permits tab 54d, and hence portion 54a, to move downwardly to engage contact 52 with contact 46. Before the end 60e moves across the plane of the legs 54h, the force exerted by spring 60 reverses to exert a vertical downward component, and a toggle action takes place causing spring 60 to move rapidly with lost motion the width of its slot 60a, minus the thickness of member 54, to engage along the upper margin of its slot as depicted in FIG. 23 and ldrive tab 54d downwardly and close contact 52 upon contact 46. In the closed position of the contacts, shown in FIGS. 4 and 23, the force developed in spring 60 applied through the upper side'of slot 60a against tab 54d is added to the aforementioned prebending stress in member 54 to hold contact 52 against contact 46. Overtravel of lever 62 in the clockwise direction is limited by engagement of one of the projections 62C with a tab 58C which overlies such projection.

Assuming that contact 52 is closed against contact 46 as shown in FIG. 4, if drive lever 62 is pivoted clockwise about its notch 62b the end 60el of spring 60 will .move downwardly along an arc and be compressed. This erted on tab 54d is decreased which reduces the contact engagement pressure. When notch 62a is in line with legs 54b the vertical component of force exerted by spring 60 on member 54 becomes zero. As lever 62 continues erted by spring 60 reverses and a position is reached where the upward force exerted by spring 62 on member 54 is balanced by the downward forces exerted by legsl 54b and a balance of forces exists. Only the aforementioned prebending stress of member 54 provides contact engagement pressure. Any additional clockwise movement of lever 62 increases the vertical component exerted by spring 60 and legs 54a will move the distance of slot 60a (less the thickness of member S4)` and spring 60 will toggle member 54 rapidly upwardly to move contact 52 from engagement with contact 46. Member 54 is limited in upward travel by engagement of therupper surface of its tab 54d with stop finger 58d which is an integral part of member 58. Similarly, the integral projections 62C on drive lever 62 engage the lower surfaces of recesses 42bformed in base 42 to limit overtravel movement ofthe lever inthe clockwise directiton.

Between drive lever 62 and diaphragm 30d a lever moy tionmultiplying and `range differential adjusting system is interposed. Referring particularly to FIGS. 3, 4, 8, 9,'

l0 and 15, the motion multiplying system includes a thrust plate 66, a range lever 68, a cut-in lever'70, a cut-out `lever '72, a stabilizing leafV member 74 anda biasing spring 76. Thrust plate 66 bears centrallyragainst'the diaphragm 30d, and diametrically, opposite legs 66a bear at their arcu- `ate` upp'er ends against the outer arms 68cof`range lever 68. Lever 68 bears at its one end 68b against the Gdge i of ar range jadjusting cam 78. At Ythe tip of its opposite angularly upward end 68d, lever 68 bears againstthe lower sides of the levers l and 72. Lever 70 pivots against the lower end of anadjusting screw 80, and lever -72 bears at its corresponding end against the lower end of an adjusting screw 82.

Bias spring 76 seats at its upper end in a recess 42d the endsl of the outer legs 74a and 74b, respectively, and

the plate 66 is spot welded on its upper surface to the end of the central leg 74C of member 74 `with the legs 66a or" plate 66 straddling the'outer margin of leg 74C. Range ,lever 68 is spot welded at its end 68b tothe intermediate connecting bight 74d of member 74. .This assembly is secured and located in base 42 by means of spaced downwardlyV projecting lugs 42e formed*y in the base molding which penetrate openings 74e formed in leaf member 74. Oppositely disposed tabs V74jc formed in the marginof the latter openings grip the sidesof lugs 42e and dig in to prevent withdrawal therefrom. Stabilizing member 74' .provideslateral stabilizing for plate 66 and levers 68, 70 and 72 and exes to permit such plate'andlevers to move and pivot as required ofthe lever. The amount of flexing required ofmember 74-in normal operation is minimized .'by making the attachments thereto as. close as possible to the pivot points'of the levers.

VAsbest/seen in FIGS. 3, 4 and 9, lever '70 has an angularly upturned portion 70a which engages on the under 'surface of a semiHcylindrical boss 62d formed onY drive f1ever6'2.' Lever 72 has a generally C-shaped free end 72a which overlies the boss 62d in a recess 62e formed in lever 62V and engages with boss62d to pivot lever 62 clockwise underl decreasing power element pressure changes as will hereinafter-be explained. K Range `adjusting cam 78 is provided with a centralV opening andj is mounted on a, cylindrical boss 42g formedfon basew42. A spring washer 86 frictionally gripping the periphery of an inner concentric boss 42fbearsragainst cam f78ftorholdit against axial displacement." `"A member 88 ijournaled for rotational movementh in mounting bracket. f

. 36 hasa lug88z which interfits withcam 78 in an opening '78a formed -in the latter. On the outer side of bracket 36vmember 88 penetrates and vis non-rotatably upset over` a U-shaped member 98. to'which range adjusting knob 34 lis'fitted.. The vportion 88h hasl al triangular shaped high point 88C (see FIG. 17) which whenknob y34 is @turned toV its ,counterclockwise .extreme limit (when looking in from `the left in FIG. l) engages the end-62f 'of a hook aportiori62g ofvdrive lever 62 to'pivot the latterto a' clockwise extreme position .wherein it manually toggles member 54 to and holdsV it in a position disengagingA contacts 152 and .46., The lastmentioned extreme limitlis deter- .rninedwhe'n member 9,0 eng'ages a raised projection 36a "struckliip from the bracket 361; j Y .ln `one preferredfembodirnent of `will be the pressures in power element -30 at which conl.tact 52 will be engaged and subsequently disengaged from contact 46. l

Let it be assumed that the contacts 52 and 46 are initially open as depicted in FIG. 3, and that cam 78 is given an intermediate adjustment depicted. Now if element 40 is subjected to an increasing temperature, the pressure in chamber 38 will increase and diaphragm 30d will move upwardly. Thrust plate 66 moves upwardly with diaphragm 30d which in turn pivots range lever 68 counterclockwise at its point of engagement with the edge of cam 78. Such movement of lever 68 causes both the cut-in vand cut-out levers 70 and 72 to be pivoted` clockwise about theirl pivot points on the ends of differential adjusting screws and 82." As cut-in lever 70 continues to pivot clockwiseit ultimately engages the lower side of boss 62d of drive lever 62. Further clockwise pivoting of lever 70 62 attain the positions depicted in FIG. 4.

Now assume, as a result of closure of contacts S2 and 46 and operation of refrigerating apparatus controlled by such contacts, that the temperature to which temperature responsive element 46 .is subjected decreases. This causes a reduction in vapor or gas pressure in chamber 38 and diaphragm. 30d moves downwardly. Bias spring 76 acting on cut-out lever 72 causes the latter and range lever 68 to pivot counterclockwise and clockwise respectively in following the ,downward movement of diaphragm 30d. Ultimately the C-shaped end .72a of cut-out lever 72 engagesV the boss y62d on its upper side and pivots drive lever 62" clockwise. When lever 62 is pivotedclockwise sui'iciently contacts 52 and 46 are toggled opened as hereinbefore described. As will be understood the force exerted by spring 76must be suiiicient to eifect `operation of the VsnapV action switch mechanism but should not have a- `spring rate greater than necessary to minimize the loading v on diaphragm 38d. Spring `rates in the range of 2 to `3 lb.

per inclihave proved to be satisfactory for spring 76.

It will be apparent that the leversl k68 and 70 or 72 pro- .vide considerable motion amplification for any upward or derlie and'overlie the boss 62d of drive lever 62 determines the differential between cut-in and cut-out toggle operation to close and openV the contacts 52 and 46. -This differential is adjustable in accordance with the adjustment Of the screws 8i) and 82. Cut-in andV cut-out differential adjustments are initially established by subjecting element 48 to a low cut-out temperature, say 20 F. for a given lintermediate adjustment of cam 78.. When element 40 is stabilized at 20 adjusting screw 82 is adjusted topivot lever 72 counterclckwise and engage boss 62d of drive cam 8 its i peripheral form will be `like that depicted' in FIG. 7. As viewed in FIG. 7,'. if cam is rotated clockwise the 'radial distance n betweeirits point of engagement wi'ththe end'68b of range lever'. 68 andl its, axis, of rotation decreases thereby causing the end 68b to' move upwardly asmemberh68 pivots on the ends of legs .66a of thrust plate. Consequently lever "pivots clockwise as viewed in FIGS.y 3 andljvthereby low-v ering its end 68d which in turn causes cut-in and cut-out levers 0 and 7,2tQ .pivot counterclockwiseabout the ends kof the differential adjusting screws 80 andy S3. As will hereinafter be apparentthe higher the position of the end' 68b of range'glever 68as established bycam78, the higher lever 62 and is continued until toggle action 'of the contact operating'mechanism occursand opens contacts S2 and 46.V If'it is desired that contacts 52 andf46 reclose at Va 10 yhigher temperature, thenv element 40 will lnext be subjected and stabilized at such a temperature, eg., 30 F.

and adjusting screw 80 isturned to pivot lever 70 clock- .wisevon-.end'68dof lever 68 to engage boss 62d and pivot drive lever'. 62 until the pointis reached where the Contact operating mechanism is toggled to :close contacts 52 and 46. Y'Thereafter for any given positioning of cam 78 the cut-in andcut-out temperatures will lalways have the same fixed differential. y

FIGS. 14 to 16 illustratela modiiied form ofjarcontrollery wherein the"cutlin `point is xed and y-do'es not change with .change in positioning of therange adjusting {cam'78 which only changes-the cutout point. The modified controller for the most part isjexactly lthe same. as the aisee-ie Vp artsibear identical reference numerals. Differences re- `s1de only in the form and arrangement of the range and fcut-in levers, and to a slight extent in the stabilizing leaf member 74. The modified version employs range lever 96 and a cut-in lever 98 of the form best shown in FIG. 16. Range lever 96 has an end 96a which on its lower surface is spot welded to the connecting bight 74d of leaf member 74 and engages on its upper surface with the edge of range cam 78. Lever 96 has an arm 96h which has an inverted V-shaped bearing surface 96C against which the lower surface of cut-out lever 72 bears. Cut-in lever 98 on the lower surface of its end 98a is spot welded to Varm 74a of member 74, and intermediate its ends is provided with a widened substantially `U-shaped bearing portion 98b that seats on its lower surface on the upper surface of thrust plate 66. The opening 74g in the leg 74c is suitably widened to afford clearance for bearing portion 98h. At its other end lever 98 is provided with an end portion 98e which engages with the boss 62d of drive lever 62. The end 98a of lever 98engages the end of adjusting screw 80 and pivots thereon as thrust plate 66 and diaphragm 30d move up in response to pressure changes in diaphragm chamber 38 to engage and pivot drive lever counterclockwise. Cut-out lever 72 in operative action pivots on the end of adjusting screw 82 and is driven upwardly by range leverY 96 and moved downwardly by spring 76 to follow range lever 96 and thrust plate 66 as diaphragm 30a' moves downwardly. It will be apparent that adjustment of cam 78 will only affect the point at which cut-out lever will be effective to toggle Ycontact 52 open, and that once adjusting screw 80 is given a calibration adjustment the cut-in point will be lixed. The modified version has been found useful when it is desired to provide evaporator defrost in refrigerators after each cycle of compressor operation. By setting the cutin point above freezing temperature (34 to 40 F.) the evaporator will have to reach this temperature before the compressor is again engaged by closure of contacts 52 and 46. This affords some melting of frost each cycle, and ,before the same can accumulate to any considerable extent.

` FIGS. 17 to 19 illustrate another modified version of the control devices before described in conjunction with y FIGS. l to 15, 22 and 23 and FIGS. 14 to 17. This secj ond modified version affords alarm actuation in the event ,the temperature in the refrigerated spaces exceeds a predetermined temperature due to failure of the refrigerator compressor or the like. This version is like that before described in conjunction with FIGS. 1 to 13, 22 and 23 but employs a modified terminal member 100 in place of terminal member 58, and an additional spring member 102, terminal member 104 and modied drive lever 105. As shown in FIG. 17 member 100 does not have astop vtab such as 58C and spring member 102 is secured between member 54 and base 42 by screws 56. Terminal member 104 is secured to base 42 in partial overlying relation to terminal member 48. As best shown in FIG. 18, an intermediateportion 104a is secured to base 42 in insulated spaced relation to an underlying portion of terminal 48 by means of an insulating spacer 106, washer 108, and

screw 110. Y n

Member 102 has parallel arms 102a and 102b which are engageable by the projections 105C of drive lever 105.

It has a right angle offsetv arm 102C integrally connected ij65 against base 42. Screw 116 permits calibration of thev j opening point of contacts 112Yand 114. VA modified end closure` member 118 is used to close the end of base 42 around the three terminal members 48, and 104. j In normal operation contacts 112 are closed to contacts 114,V and will remain so closed unless the closure of previously described main contacts 52 and 46 are ineffective .to energize the refrigerator compressor. In the latter event the temperature of the refrigerated space will continue to rise, and assuming that the controller is in the loperating condition wherein main contacts 52 and 46 have closed, as shown in FIG. 4, any furtherincreases in temperature will effect further counterclockwise pivoting Vof drive lever 62. The projections C of leverV 105 then engaging the lower surface of arms 102a and 102b will move the same upwardly against the initial downward bending stress imparted thereto. Ultimately arm 102C rises suiciently to disengage contacts 112 from the contacts 114. Thus if common terminal 100 and alarm ter- Vminal 104 are connected appropriately with an alarm device interruption of engagement of contacts 112 and 114 will cause operation of such alarm device in a Well known manner to call attention that dangerously high temperatures are being developed in the refrigerated space.

With temperature element 40 subjected to the temperature at which it is desired to have alarm contacts 112 and 114 open and the controller stabilized at such temperature screw 116 is turned against base 42 to cause portion 104b of member 104 to ride up the shank of the screw until contact 114 engages contact 112. Screw 116 is then readjusted a slight amount in the opposite direction until contacts 114 just disengage from contacts 112.

FIGS. 20 yand 21 disclose another alarm version of the basic controller which is provided with normally open alarm contacts. In this latter embodiment another stationary terminal member 120 is used in place of terminaly member 104. It is mounted to member 42 in the same manner as the replaced member 104. Spring member 102 is provided with a contact 122, and upon upward movement of arm 102e engages with an adjustable screw 124 that serves as a stationary contact. Engagement o f contacts 122 and screw k124, Yas will be apparent, completes a circuit between common terminal member 100 and alarm terminal member 120. With the controller' stabilized at the temperature at which it is desired to have contacts 122 close to screw 124, the latter is turned until it disengages from contacts 122 and then reversely turned until it just engages with contacts 122.

It will be noted that the molded drive lever 105 show n in connection with both alarm versions does not have the overhanging end as does lever 62 having an end 62j to afford a manual off position in conjunction with portion 88C of member 88. However, if a manual oft position is desired a lever like lever 62 may be used in place of theV lever 105 in either of the aforedescribed alarm versions. If it is desired to omit the manual Vo position in either the straight range version described in conjunction with FIGS. 1 to 13 and 22 and 23, or the constant cut-in version described in conjunction with FIGS. 14 to '17,

,the modified drive lever 105 should be substitutedfor drive lever 62. K

FIG. 24'illustrates a modilication in respect `to external portions of modified terminal members 136 that can be -used in place of those used in the version of FIGS. 1 to which varies in a linear relation to temperature changes Y `maybe preferred. Such a power element is disclosedin the Cox Patent No.2,698,7 66. Y We claim: v j f j 1. In combination in a thermostatic switch, alsnap acting switch mechanism having an operating member movable to one extreme position wherein said mechanism assumes one stable operating condition andmovable to another extreme position wherein said mechanism assumes another stable operating condition, a thermally responsive power element having a diaphragm which moves inwardly and outwardly in accordance with changes in pressure of theV fluid fill in said element, and a motion transmitting mechanism between said diaphragm Vand said operating member comprisinga first lever to drive saidyop-` eratingA member to said one extreme position when said diaphragm moves outwardly,.a second lever and 'a spring y `motion transmitting means mechanism further comprises means adjustable to various positions to afford changes in the outward and inward positioning of said diaphragm required to` effect the vaforesaid drive .of said operating member to its oppositeextreme.positions.

4. The combination according to claimy 3 wherein said motion transmitting means further. comprises additional adjustable means `for each of saidiirst and second levers affording changes in ther differential between the aforestated operating member operations provided by said first and second levers. v f Y Y 5. The combination according toclaim 1 wherein upon reversal from inward tooutward movement of said diaphragm and vice versa said first and second levers movewith lost motion before driving saidy operatingmember.

6. The combination according to claim 1 wherein said power element diaphragm assumes definite positions in a linear relation to the pressure developed by the internal uid fill. I 1` i l 7. The combination according to claim l wherein said motion transmitting means further comprises anadjustable member, a third'lever pivoted at one end 0n said yadjustable member and engagingat leastone of said first and second levers at its other end, and a member movable rectilinearly with said diaphragm and engaging said third lever intermediate the ends of the latter, said adjustable member being adjustable to various positions to and said first, second and third levers are attached, said flexible metal member providing lateral stability for the member and levers attached theretoy while flexing upon rectilinear movement of said last mentioned member and pivotal movements of said levers.

12. The combinationpaccording to claim l1 wherein said exible member has portions with spacing therebetweento facilitate flexing of such portions individually in accordance with the movement or pivoting of the member and individual levers attached thereto.

13. The combination according to claim 1 wherein said motion' transmitting means further comprises ani. adjustable member, a third lever pivoted at one end on said adjustable member and engages said second lever at its other end, and a member movable rectilinearly which engages said first lever and third levers intermediate their' respective ends, said adjustable member being adjustable to various positions to correspondingly change the distance between said diaphragm and the pivot point at said one end of said third lever to afford change in the inward travel of said diaphragm required to effect the aforestated operation of said operating member by said secondr lever.-

14. In combination, in a thermostatic control device, a snap action switch mechanism comprising amolded insulating base, an electrical terminal member having a stationary contact tip mounted on said base, a second electricalterminal member mounted on said base in spaced f relationrto first mentioned terminal member, a thin flexible electrical conducting member having an end engaging j and secured to said base by said second terminal member and having a portion on which a contact tip is mounted correspondingly change the' distance between said diaphragm and the pivot point at said one end of said third lever to afford changes in the outward and inward travel of said diaphragm required to effect ther aforestated operations of said operating member.

8.1The combination according to claim 7 wherein said third lever engages both said first and second levers at its other end. l f' f 9. The combination according to claim 7 wherein said and said first lever is,y engaged intermediate its ends directlyby said member movable rectilinearlyfwith said diaphragm. v

i 10. nThe combination according to claim 7V wherein adjustable pivot-abutments areprovidedV at the correspond- Y ingends of said firstland second levers which accordingV to their adjustments determine the. differential betweenv the aforestated operating actions imparted tol said operating member by s-aid Vfirstand second levers. f

and second levers at its other end, af member movable rectilinearly with said diaphragm and engaging said third lever intermediate the ends of the latter,` and a thinflexible metal member to lwhich the lastmentioned member kthird lever engages only said second lever at its other end in line with the first mentioned contact tip, said portion 'of said exible member having a centralopening, an

operating levervpivoted on an inner edge of said portion,

a snap member having a transverse slot adjacent one end through which said portion of said flexible member extendsand engaging at its other end with saidV operating lever, said operating lever being pivotally movable in opposite directions across the plane of said flexible member to provide lost motion, snap action toggling of said portion of said flexible member from one stable positionV to another, a thermallyy responsive power element having f a diaphragm which moves inwardly and outwardly in accordance with changes-in pressure of the fluid lill in said element, and a motion transmitting mechanism between said diaphragm and said operating lever comprising a first lever to drive said operating lever in one direction when said diaphragm moves outwardlya second lever and a' spring biasing said second lever to drive said operating lever in its opposite direction when said diaphragm moves inwardly.

15 The combination according to claim 14 wherein said spring only exerts a bias sufficient to afford the'aforementioned drive of said operating member by Said second lever, and said diaphragm on outward movement not being lsubjected to any` mechanical forces beyond that imposed by said switch mechanism through said operatingfmember before the latter moves to said one extreme position.

16. The combination according to ,claim 14 wherein Y said motion transmitting means further comprises an adjustable-member, a third lever pivoted at one end on said adjustable member and engaging at least one of said first;

and second levers at its other fend, and a member movable rectilinearly-with said diaphragm and engaging said third klever intermediate the ends ofthe latter, said adjustable member being adjustable to various positions to correspondingly changethe distance between said diaphragm and the pivot point at said one end of said third lever to afford changes in'y the .outward and inward travelof said diaphragm required to effect the aforestated operations of said operating member.

17. `The combination according'rto claim 16- together withra second'adjustable member-operable to a given ex- 11 treme position to move said operating lever in said opposite direction and hold it in a position affording disengagement of said contact tips independently of positioning of said first and second levers.

p 18., The combination according Yto claim 17 together with means for effecting simultaneous adjustments of the rst mentioned and second adjustable members which are effective respectively at different ranges of adjustment of the last mentioned means.

19. The combination according to claim 17 wherein said flexible member is anchored at two spaced points to said insulating base. 20. The combination according to`claim 14 wherein said motion transmitting means further comprises an adjustable member, a third lever pivotal at one end on said adjustable member and engaging at least one of said secvlond and third levers at its other end, a member mov- -ber`and pivotal movements of said levers.

21. The combination according to claim 14 together lwith a third electrical terminal member mounted on said base and having a contact tip thereon and a resilient elec- -trical conducting member having a contact tip in line with that of said second terminal member mounted on said base in engagement with said second terminal member, said resilient member normally assuming a position wherein its contact tip'isin one electrical condition with respect to that of said third terminal member, and said ance with such adjustment.

operating lever upon movement in Ysaid one direction beyond the point required to operate said switch flexing said resilient member in a direction affording the opposite electrical condition between its contact tip andV that of said third terminal member. Y

22. The combination according to claim 21 wherein said resilient member normally assumes a position whereinits contact tip engages that of said third terminal member and is flexed to disengage therefrom by the last mentioned movement of said operating lever. t.

23. The combination according to claim 21, wherein said resilient member normally assumes a position Wherein its contact tip is disengaged from that of said third terminal member and is flexed to engage its contact tip with that of said third terminal member by the last mentioned movement of said operating lever.

24. The'combination according to claim 21 together with means for adjusting said third terminal member so that change from one to the'other electrical condition of the contact tips of said third terminal member and said resilient member requires different degrees of movement of said resilient member by said operating lever in accord'- References Cited in the ile of this patent -UNITED STATES PATENTS 2,587,746 May Mar. 4, 1952 2,617,312 Prentice Nov. 1l, 1952 2,885,513 j Judd May 5, 1959 l 2,889,432 Miller June 2, 1959 2,905,781 Cherry 1 Sept. 22, 1959 i 2,905,782

Chapin et al. Sept. 22, 1959 

1. IN COMBINATION IN A THERMOSTATIC SWITCH, A SNAP ACTING SWITCH MECHANISM HAVING AN OPERATING MEMBER MOVABLE TO ONE EXTREME POSITION WHEREIN SAID MECHANISM ASSUMES ONE STABLE OPERATING CONDITION AND MOVABLE TO ANOTHER EXTREME POSITION WHEREIN SAID MECHANISM ASSUMES ANOTHER STABLE OPERATING CONDITION, A THERMALLY RESPONSIVE POWER ELEMENT HAVING A DIAPHRAGM WHICH MOVES INWARDLY AND OUTWARDLY IN ACCORDANCE WITH CHANGES IN PRESSURE OF THE FLUID FILL IN SAID ELEMENT, AND A MOTION TRANSMITTING MECHANISM BETWEEN SAID DIAPHRAGM AND SAID OPERATING MEMBER COMPRISING A FIRST LEVER TO DRIVE SAID OPERATING MEMBER TO SAID ONE EXTREME POSITION WHEN SAID DIAPHRAGM MOVES OUTWARDLY, A SECOND LEVER AND A SPRING BIASING SAID SECOND LEVER TO DRIVE SAID OPERATING MEMBER TO ITS OTHER EXTREME POSITION WHEN SAID DIAPHRAGM MOVES INWARDLY. 